Magnetic separator



Dec. 19, 1944. R H. STEARNS MAGNETIC SEPARATOR Filed June 21, 1943 3 Sheets-Sheet 1 INVENTOR. flaw/11 /2. Jmw/s Dec. 19, 1944. R. H. STEARNS 2,365,603

MAGNETI C S EPARATOR Filed June 21, 1943 3 Sheets-Sheet 2 INVENTOR. flask/m fl. J7me:

Dec. 19, 1944. s s 2,365,603

MAGNETIC SEPARATOR Filed June 21, 1943 3 Sheets-Sheet 3 sroP O\ 1/4 7 .INVENTOR.

A BY ATTOAIVEK Patenteaiaea 19, 1944 MAGNETIC SEPARA'I'OR Roswell H. Stcarns, Wauwatosa, Wis., assignor to Stearns Magnetic Mfg. 00., Milwaukee, Wis., a corporations! Wisconsin Application Jane 21, 1943, Serial No. 491,652

12 Claims.

LHIS invention relates to magnetic separators. In the practice of separating magnetic material from non-magnetic material, as heretofore followed, where the magnetic content of the mixture varied all the way from material of high permeability to material of very low permeability, it was customary to use one type of machine for first separating out the magnetic material of high and medium permeability and thereafter use a different type of machine for separating out the material of low permeability.

Further than this, where the manufacturer of ceramic ware, for instance, was required to separate magnetic material from a batch of nonmagnetic material of one color, and thereafter to separate magnetic material from a batch of non-magnetic material of a diiferent color, extreme difficulty was experienced in properly and quickly cleaning the machine to prevent some remaining part of the material of one color becoming mixed with a batch of material of a different color.

In high quality ceramic work it is the usual practice to utilize powdered ceramic material in which the magnetic content is only a relatively -small percent of the entire mixture, and in this work it has been found that if even a very minute amount of magnetic material is left after separation, the entire batch of material is spoiled, thus producing a high monetary loss as the presence of the remaining impurity is not usually noticed until the product is completely finished.

Objects of this invention are to provide a magnetic separator which will meet the exacting requirements and overcome the diificulties hereinabove noted, and which will secure an extremely high degree of absolute purity of the material after it has been passed through the separator, and in addition, to provide a magnetic separator which although having these characteristics is economical both as-to first cost and as to expense of operation, and which can be built either in small or large sizes to respectively fill the needs of a small or large manufacturer, and which can be employed to handle relatively small batches of material or to handle large quantities of material in a substantially continuous manner with an interruption in its continuous operation of only a second or two at widely spaced intervals.

Further objects are to provide a magnetic separator which fulfills a two-fold purpose of separating out, in one and the same machine, material of high permeability and material of very low permeability as well as material of all degrees of permeability in between these limits.

Further objects are to provide a magnetic separator which utilizes the principle of temporarily holding the easily magnetizable material in clinging relation to a pole of the machine and simultaneously deflecting the difiicultly magnetizable material, which cannot be held, into the discharge chute, and to provide means for periodically dislodging and discharging the clinging material into the discharge chute and simultaneously arresting the feeding of the mixed material to the machine with an interruption, of what would otherwise be a, continuous peration, of only a second or two, provision also being made for the automatic striking of a sharp and sudden blow to insure the discharge of the clinging material even though the clinging material or adjacent parts of the machine may have acquired residual magnetism.

Further objects are to provide a magnetic separator which canbe easily cleaned so that batches of material of different colors, for instance, can be handled by the machine and the machine can be easily and quicklycleaned after each batch of material, thereby avoiding any contamination or mixing of successive batches of material.

Further objects are to provide a magnetic separator which is foolproof in its operation, and which can be used by an inexperienced person with absolute assurance of success.

.Further objects are to provide a magnetic separator which is very simple in construction and which has few moving parts, which parts in the majority of the tim the separator is in operation remain stationary and only come into operation for a brief instant at widely spaced intervals.

An embodiment of the invention is shown in the accompanying drawings, in which:

Figure 1 is a side elevation of the separator, such view having parts broken away.

Figure 2 is an enlarged View of a portion of the separator, with parts broken away and in section, such view showing the-normal position of the parts when the separator is in operation.

Figure 3 is a view corresponding to Figure 2 showing the position of the parts when the separator has stopped functioning.

Figure 4 is a detailed fragmentary sectional view showing the position of the parts when the separator is functioning in its normal manner.

Figure 5 is a view corresponding to Figure 4 showing the position of the parts when the separator has been stopped.

Figure 6 is a view corresponding to a section approximately on the line 6-6 of Figure 2 with parts broken away.

the separator comprises upper and lower yoke portions'l and 2 which terminate in upper and lower poles I and 4. The yokes are Joined by means of a core I which carries the energizing winding I. If desired, the separator may be made with poles at opposite sides as indicated in the drawings so as to get duplex operation of the separator, or if desired the separator may be made as a single unit. If it is used for duplex operation, the feeding and discharge means will be duplicated for each pair of poles.

The poles I and.4 are sharply tapered and have their tips arranged in proximity to each other with the lower pole tip set inwardly of the overhanging upper pole tip. The chute is indicated by the reference character 1 and is provided with a rear wall I conforming to the outer face of a portion of the upper and lower poles I and 4, as seen most clearly in Figure 4. The chute is formed of magnetic material and is adapted to be held tightly against the poles by the magnetic pull exerted by the poles.

However, in addition to the attraction of the chute itself by the poles, auxiliary armature portions 8 are carried on opposite sides of the chute I and are adapted to be attracted by the projectting portions i0 formed on opposite sides of the lower pole 4. Slotted guiding ears II are carried by the chute and are adapted to be loosely guided by means of pins i2 projecting from opposite sides of the lower pole. Preferably the guide strips ii are of non-magnetic material.

The chute is loosely supported by means of a pair of apertured fingers I! which loosely ride on supporting pins i 4 carried by the lower pole 4. It is preferable to brace the side walls of the chute by means of the upper angle iron I! and by means of the lower angle iron II. The upper angle iron additionally serves as a guard means to prevent magnetic material when suddenly dislodged from the chute in a manner hereinafter to appear from passing to the right as viewed in Figure 5.

A wedge-shaped elongated vane constituting a dividing member is indicated by the reference character i1 and is normally positioned below and slightly inwardly of the upper pole I. This dividing member is rigidly carried by means of a rock shaft i8 and is mounted on the stationary support is, such support having a V-shaped inner portion to provide a discharge chute II for the magnetic material and a discharge chute 22 for the material which has been freed of magnetic content. x

The rock shaft carries at one end a pair of levers 23 and 24. A relatively heavy spring 2! is attached to the lever 23 and tends to rockithe divider I 1 into the position shown in Figure 5. The shorter lever 24 is connected by meansfof a link 28 to an armature 21 pivoted approximately centrally on the bolt II carried by a no magnetic-supporting member 20. The arms. re 21 is adapted to be attracted by the projecting pole 80 formed on the upper yoke I when the separator is in operation.

Before the members 8 and II come into actual engagement, the chute is in engagement with the outer face of the upper and lower poles and is slightly flexed as the poles 9 and ,II come into contact. This insures an absolute and tight engagement between the magnetic chute and the polesand prevents the formation of any air gap at these points.

2,sss,sos' I Themateriallsfedfromahopperfl intoa vibrating feed chute or trough I. This tl'dlllh is carried by spring supports II and is vibrated by means of the electromagnetic vibrator 44. This vibrator is made adjustable by means of the screw II in a well known manner. The 'feed trough and vibrator are carried by a support GI which is pivotaliy-mounted on opposite sides as indicated at I! and which is provided with a curved slot II through'which a locking screw II extends so as to lock the support and. consequently the feed trough at any desired angle.

If desired a smoothing member 4. may extend across the trough and may be mounted for rotation on supports 4| independently of the trough. The member 4| is adapted to be rocked or adjusted by means of the hand wheel 42 so as tosmooth the material out as it passes under the member 44 into a thin layer or into a thicker layer, depending on the setting of the member 40.

The separator is controlled by means of a switch indicated generally at 0. This switch may be a two-button toggle switch having a start and stop button indicated at 4| -and 44 respectively. The switch controls the supply of alternating current to the control coil of the contactor indicated generally at 46 and to the half wave rectifier indicated at 41. The half wave rectifier 41 furnishes current to the winding 4I of the vibrator 34 and the value of the current is determined by the adjustment of the rheostat 4I which in turn adjusts the rate of feed of the material. The contactor 4] is adapted to connect the winding I of the separator with a source of direct current. If desired, a rheostat II and an ammeter 5| may be placed in series with the coil I so that current passing through the coil may be set at any desired value.

In the operation of the apparatus, the operator closes the switch 43 by depressing the start button and instantly energizes the contactor 40 and simultaneously supplies the half wave rectifier 41 with alternating current. Thus the main magnet of the separator is energized and at the same time the feed of the materialstarts. Material is fed from the feed trough I2 and is projected against the back wall I of the chute I. The magnetic material of high reluctance will not adhere to the powerfully magnetized rear wall I of the chute, which in effect constitutes practically an extension of the upper and lower poles. The highly reluctant magnetic material will be premagnetized by the pole I and will be deflected by the pole 4 to the left of the divider II, as viewed in Figure 4, and will pass into the discharge chute iii. The nonemagnetic material will pass to the right of the divider i! into the chute 22. The material of greater permeability will adhere to the back wall 8 of the chute.

After the separator has operated for a predetermined interval, a certain amount of medium and high permeabilitymagnetic material will collect on the back wall 8 of the chute. The operator at suitable intervals presses the stop button 44, thus opening the switch 43 and the contactor 48 and stopping the supply of pulsating current to the coil 48 of the vibrator 34. It is to be noted that by means of this arrangement the feed is instantly stopped simultaneously with the deepergizing of the separator. It has been found with this type of feed mechanism that the feed absoas, see Figures 2 and a, rocks the divider I! in a clockwise direction to the position shown in Figures 3 and 5, the armature 21 rocking in a counterclockwise direction. The clinging material is not jarred free of the back wall 8 of the separator until the divider l I strikes the angle iron or bracing member 16 of the chute I and suddenly drives the chute a slight distance to the right to the position shown in Fig es 3 and 5. This dislodges any clinging materia from the chute 'I. It is to be noted that the material of medium and high permeability frequently becomes permanently magnetized and adheres to theJJnhute even after the separator is deenergized and consequently has to be dislodged by means of the sharp and sudden blow struck by the divider 11. It is to benoted that before any jar is imparted to the chute I, the divider has moved over to the right, as viewed in Figure 5, and cuts off communication with the chute 2 2 and insures .that all dislodged magnetic material will be.defiected into the discharge chute 2|.

The operator immediately presses the start button 45 andthus closes the switch 43 simultaneously energizing the separator and starting the feed and rocking thela fmature 21 back from the position shown in Figure 3 to the position shown in Figure 2. This rocks the divider I! back to its normal position and the magnetic chute 1 is drawn into binding engagement with the poles 3 and 4. In addition to this. as previously described. the small pole pieces 9 and ill on opposite sides of the chute come into contact with eachother slightly after the back wall 8 of the chute has engaged the outer faces of the poles 3 and 4, thus slightly flexing the chute and holding it in bindin and intimate contact with the poles.

It is to be noted that the chute is formed of relatively thin magnetic sheet material and consequently only a negligible portion of the flux is short-circuited by that portion of the chute that extends from one pole tip to the other. It is to be noted also that the chute is inintimate contact with the poles of the magnet and consequently an intense magnetic zone or field is produced at the inner surface of the chute where the material contacts as it is being fed inwardly against the chute.

The dislodging of any clinging material from the chute is substantially instantaneous and therefore the operator need only depress the stop button and immediately thereafter depress the start button. An interval of perhaps a second or two is all that is needed for this operation and therefore the interruption of what would otherwise be continuous operation of the separator is extremely brief. Thus it will be seen that though the separator is designed primarily for separation of batches of material, it nevertheless can be used for substantially continuous operation.

By utilizing the principle of having the separating chute form in effect a continuation of the upper and lower poles, it will be seen that an extremely intense field is produced and that the material, as it is fed inwardly against the back of the chute, comes into actual contact with the highly magnetized chute itself and thus any material of medium or high permeability will cling to the chute, whereas the material of relatively low permeability will pass downwardly and fall freely from approximately the lower tip of the upper pole piece past the lower pole piece, it being noted that the back 8 of the chute is curved inwardly at this point. The freely falling premagnetized,

highly reluctant material will be deflected by the lower pole l to the left of the divider H. The clinging material is dislodged by the substantially instantaneous stopping of the machine and the sudden and severe jarring of the chute, the normal operation of the separator being substantially instantaneously resumed as hereinabove described.

The separator provides the two-fold function of separating out highly permeable material and also material of very low permeability as well as material of all degrees of permeability therebetween. This invention, therefore, provides in one and the same machine means for taking out not only the highly permeable but also the highly reluctant material without requiring two separate machines or two separate operations as has heretofore been the practice.

One of the features to be noted particularly is the ease with which the separator can be cleaned. All of the parts are open and can be brushed out with the utmost ease. This provides a great advantage for a manufacturerwho wishes to separate magnetic material from a batch of colored material and thereafter separate magnetic material from another batch of a different color with assurance that there will be no mixing of one color with another color. In view of the fact that he can run one batch through the machine and thereafter quickly dust out the separator, as all portions thereof are readily accessible, it is apparent that he can run the second batch of a different color, for instance, through the separator without any danger of contamination from the previous batch.

In high quality ceramic work the manufacturer cannot afford to have even a minute percent of magnetic material remaining as even a very minute quantity will ruin the entire batch. It has been found that with this separator substantially absolute purity of the final product is obtained. Also it has been found that this sep arator will operate successfully in separating out magnetic material of widely different permeabilities and also of widely different relative percents.

The separator is of very simple construction and can be economically built in any desired size to fit the needs of any manufacturer.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A magnetic separator comprising an electromagnet having an upper and a lower pole, a movably supported chute extending across said poles, magnetically operated means for holding said chute in intimate contact with said poles when said electromagnet is energized, electrically operated means for feeding material into said chute, dividing means located below said upper pole and biased for motion in a direction to strike said chute and drive said chute outwardly away from said poles when said electromagnet is deenergized, magnetic means energized from said electromagnet for normally holding said dividing I means against motion and releasing said dividing means when said electromagnet is deenergized, and means for simultaneously stopping the feeding means and deenergizing said electromagnet, whereby said dividing means will strike said chute and dislodge clinging material.

2. A magnetic separator comprising an electromagnet'having an upper and a lower pole, a movably supported chute formed of magnetic material and extending across said poles, magnetically operated means for holding said chute in intimatecontact with said poles when said elec-.

tromagnet is energized. electrically operated means for feeding material into said chute, di-

viding means located below said upper pole and biased for moti o nAn a direction to strike said chute and drive said chute outwardly away from said poles when said electromagnet is deenergized, magnetic means energized from said electromagnet for normally holding said dividing with the lower pole set inwardly and the upper pole overhanging the lower pole, a chute extending across the said poles, automatic feeding means for feeding a mixture of non-magnetic and magnetic material of higher and lower permeability against said chute adjacent said upper pole,

whereby the material of higher permeability will cling to said chute and the material .of lower permeability will be deflected from the discharged non-magnetic material by said lower pole, dividing means located below the upper pole, a chute for receiving non-magnetic material located on one side of said dividing means and a discharge chute for magnetic material located on the other side of said dividing means, means for simultaneously stopping said feedingmeans and deenergizing said electromagnet and rocking the said dividing means'to a position to strike said first mentioned chute to dislodge clinging material of higher permeability, said dividing means when in the striking position substantially shielding the chute for the discharge of non-magnetic material from the dislodged clinging material, and guard means for preventing the inadvertent escape of the dislodged material.

4. A magnetic separator comprising an electromagnet having an upper and slower pole with the lower pole set inwardly and the upper pole overhanging the lower pole, a magnetic chute extending across the said poles, magnetic means energized from said electromagnet for normally holding said chute in intimate contact with said poles, automatic feeding means for feeding a mixture of non-magnetic and magnetic material of higher and lower permeability against said chute adjacent said upper pole, whereby the material of higher permeability will cling to said chute and the material of lower permeability will be deflected from the discharged non-magnetic material by said lower pole, dividing means located below the upper pole, a chute for receiving non-magnetic material located on one side of said dividing means and a discharge chute for magnetic material located on the other side of said dividing means, and means for simultaneously stopping said feeding means and deenergizing said electromagnet and rocking the said dividing means to a position to strike said first mentioned chute to dislodge clinging material of higher permeability, said dividing means when in the striking position substantially shielding the chute for the discharge of non-magnetic material from the dislodged clinging material.

5.'A magnetic separator comprising an electromagnet having an upper and a lower pole and having an energizing winding, an electromagnetic feed deviceior feeding material to said separator, said,electromagnetic feed device having an operating coil, a chute extending across said poles, a divider pivotally mounted below said upper pole and biased towards motion to a position, to strike said chute and normally held in position by said electromagnet, a source of alternating current and a source of direct current, and switch means-including a contactor for simultaneously connecting and disconnecting said sources of alternating and direct current, re-

spectively, to the operating coil of said feed device and the energizing winding of said electromagnet.

6. A magnetic separator comprising an electromagnet having an upper and a lower pole and having an energizing winding, a source of direct current, a contactor adapted to'connect said winding with said source of direct current, said contactor having a control coil for closing said contactor when said coil is energized, an electromagnetic feed device for feeding material to said separator, said electromagnetic feed device havin an operating coil, a half wave rectifier connected to the operating coil of said electromagnetic feed device, a, chute extending across said poles, a divider pivotally mounted below said upper pole and biased toward motion to a position to strike said chute and normally held in position by said electromagnet, a source of alternating current, and switch means for simultaneously connecting and disconnecting said source of alternating current and the control coil of said contactor and the operating coilof said electromagnetic feed device through said half wave rectifier, whereby said switch means interrupts the alternating current and causes the contactor to interrupt the direct current when said switch means is opened. 7. A magnetic separator for separating material of higher and lower permeability from nonmagnetic material at one operation comprising an electromagnet havin a pair of spaced poles with one of said poles positioned approximately above the other of said poles, a chute of magnetizable material extending across the poles, means for feeding material into intimate contact with said chute whereby highly permeable mag netic material will be held against said chute and non-magnetic material and material of low permeability will fall from said chute and the magnetic' material of lower permeability, will be drawn into the flux path and will drop beyond the falling stream of non-magnetizable material, and means for simultaneously stopping the feed and jarring the chute to dislodge the material of high permeability.

8. A magnetic separator comprising an electromagnet having a pair of spaced poles with one be held against said chute and non-magnetic material and material of low permeability will fall from said chute and the magnetic material of low permeability will be drawn into the flux path and will drop beyond the falling stream of nonmagnetic material, and means for simultaneously stopping the feed, deenerglzing said electromagnet and jarring the chute to dislodge the held material of high permeability.

9. A magnetic separator comprising an electromagnet having a pair of spaced poles with one of said poles positioned approximately above the other of said poles, a movably supported chute extending across the said poles, said chute being formed of magnetic material and being tightly held to said poles when said electromagnet is energized, means for feeding material into intimate contact with said chute whereby magnetic material of high permeability will be held against said chute and will cling to said chute and non-magnetic material and material of low permeability will fall from said chute and the magnetic material of low permeability will be drawn into the flux path and will drop beyond the falling stream of non-magnetic material, and means for simultaneously stopping the feed, deenergizing said electromagnet and striking said chute a sharp blow to dislodge the clinging magnetic material of high permeability.

10. A magnetic separator for separating magnetic material of higher and lower permeability from non-magnetic material at one operation comprising an electromagnet having an upper and a lower pole, a first chute of magnetizable material extending across said poles and being normally held in intimate contact with said upper pole, automatic feeding means for feeding mixed magnetic and non-m netic materialagainst said chute adjacent said upper pole,

whereby the material of higher permeability will cling tosaid first chute and the non-magnetic material and material of lower permeability will fall downwardly'past said poles, the material of lower permeability becoming premagnetized by said upper pole, said material of lower permeability being drawn into the fiux path by the lower pole beyond the falling stream of nonmagnetic material, a second chute for receiving the magnetic material of lower permeability, a

' netic material of higher and lower permeability from non-magnetic material at one operation magnetic material extending across said poles and being normally held in intimate contact with said upper pole, automatic feeding means for feeding mixed magnetic and non-magnetic material against saidchute adjacent said upper pole, whereby the material of higher permeability will cling to said first chute and the non-magnetic material and material of lower permeability will fall downwardly past said poles, the material of lower permeability becoming premagnetized by said upper pole, said material of lower perme ability being drawn into the flux path by the lower pole beyond the falling stream of nonmagnetic material, a second chute for receiving the magnetic material of lower-permeability, a third chute for the non-magnetic material, movable means for jarring the clinging magnetic material of high permeability from said first chute into said second chute, and means for simultaneously causing the deenergization of said electromagnet and the stopping of the feeding means and the operation of said movable means.

12. A magnetic separator for separating magnetic material of higher and lower permeability from non-magnetic material at one operation comprising an electromagnet having an upper and a lower pole, a first chute of light gauge magnetic material extending across said poles andbeing held in intimate contact with'said poles by magnetic attraction, automatic feeding means for feeding mixed magnetic and nonmagnetic material-against said chute adjacent said upper pole, whereby the material of higher permeability will cling to said first chute and the non-magnetic material and material of lower permeability will fall downwardly past said poles, the material of lower permeability becoming premagnetized by said upper pole, said material of lower permeability being drawn into the flux path by the lower pole beyond the falling stream of non-magnetic material, a second chute for receiving the magnetic material of lower permeabili y. a third chute for the non-magnetic material, movable means for jarring the clinging magnetic material ofhigh permeability from said comprising an electromagnet having an upper and a lower pole. a first chute of light gauge first chute into said second chute, and means for simultaneously causing the deenergization of said electromagnet and the stopping of the feeding means and the operation of said movable means. v ROSWELL H. STEARNB. 

